Refrigerated truck trailers and the like have long been used to transport perishable items. Insulated partitions or bulkheads have been used to subdivide the trailer interior to define chamber portions that can be maintained at different temperatures. For example, some trailers include multiple refrigerators located at the front, rear and/or midsection of the trailer's chamber. Partitions can be used to define two or three different refrigerated interior portions, each cooled to a unique temperature by one of the refrigerators. In this way, the same trailer can transport items that are desirably kept at different temperatures. Similarly, partitions can be used to enable refrigerated goods and non-refrigerated goods to be hauled in the same trailer. Partitions can also be used to improve the haul of a partially filled refrigerated truck trailer. For example, the goods can be loaded into one portion of the chamber, which is then enclosed by one or more partitions so that only a part of the trailer chamber needs to be refrigerated. Partitions can also be used to simply separate the goods to be delivered at different locations.
Many partitions in use today are manually fit into the truck trailer by the operator. They generally include a peripheral seal and extend laterally across the trailer chamber to subdivide the refrigerated chamber. They may at times be foldable about a vertical hinge to ease handling, installation and removal. In any event, the partitions tend to be heavy, bulky and difficult to place into their proper position. To resolve these difficulties, partitions have been shaped to correspond to only one-half of the trailer width in order to weigh less, and be more easily moved and put in place. In half-width partitions, two are placed in side-by-side abutment to subdivide the chamber. To further ease handling, some partitions have been mounted on rails for longitudinal movement in the chamber. In these constructions, the partitions are usually swung about hinges for movement between operative and loading positions.
In a partition system sold by ITW Insulated Products, two half-width partitions are mounted side-by-side on a single axle that is supported on each end by a trolley. Each trolley is movable along the length of a rail attached to one of the sidewalls adjacent the ceiling. In this system, the partitions are moved together along the rails to the desired longitudinal position. When the trailer is to be loaded or unloaded, the partitions are individually swung and latched to the ceiling. The half-width partitions are less weight and are thus easier to lift to the ceiling than a full width partition. Nevertheless, this system still requires the partitions to be moved together, and to be manually lifted and latched without mechanical assistance.
In U.S. Pat. No. 6,247,740, the partitions are individually mounted on separate axles, which are each mounted on a trolley. Each trolley moves along a rail extending across one of the sidewalls, and includes a hinge assembly that swings the partition either to the ceiling or the sidewall for loading or unloading of the trailer. The half-width partitions are more easily moved than full width partitions. However, the use of a single rail positioned along each of the sidewalls requires a relatively robust rail, trolley and axle assembly to prevent the partition from pulling from the wall. The trolley and axle assembly is also relatively complicated as compared to a single-axis hinge due to its ability to move to a loading position against the sidewall or ceiling. This system also includes lift ropes to ease lifting of the partitions when positioned along the ceiling. The ropes are hooked to anchors fixed to the sidewalls to hold the partitions in place during loading of the trailer. However, a taut segment of the lift rope extends downward along the sidewall when the partition is along the ceiling, thus risking being struck and damaged during loading of the goods into the trailer.
U.S. Pat. No. 6,626,625 discloses a partition system wherein half-width partitions are each separately mounted on a pair of trolleys movably attached to a plurality of spaced apart rails. One rail extends along each sidewall and two rails along the center of the ceiling. Each partition can be independently moved in a longitudinal direction and independently swung to the ceiling. Further, a lift rope is provided for lifting and lowering the partitions. The lift rope is fed through a control mechanism whereby a pivotal cam selectively holds and releases the rope as needed. However, since the pulleys and center rails are supported by the ceiling, the system can only be used in trailers constructed with ceilings able to support the necessary loads of the partition system. Moreover, operation of the cam via the lift rope requires a minimum clearance to laterally pull the rope for releasing the cam.
Further, goods transported in a refrigerated truck trailer are typically supported on pallets that are loaded and unloaded by fork lift trucks. The fork lift truck can at times mistakenly strike a partition set up to separate two partitioned areas. As the operators generally drive the fork lift trucks quickly, they can, at times, strike the partition with considerable force. In all current rail mounted partition systems, the partitions are fastened to the trolleys that are adapted to move along the rails. Such fastening can lead to breakage of the partitions when struck during loading or unloading of the goods.